package gr.aueb.cs.mscis.chordroid.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * This class produces Sha1 hashes based on a given String
 * @author lupin
 *
 */
public class Sha1 {

	public static String getHash(String str) {
		MessageDigest digest = null;
		byte[] input = null;

		try {
			digest = MessageDigest.getInstance("SHA-1");
			digest.reset();
			input = digest.digest(str.getBytes("UTF-8"));

		} catch (NoSuchAlgorithmException e1) {
			e1.printStackTrace();
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		return convertToHex(input);
	}
	
	public static String getHash(byte[] data) {
		MessageDigest digest = null;
		byte[] input = null;

		try {
			digest = MessageDigest.getInstance("SHA-1");
			digest.reset();
			input = digest.digest(data);

		} catch (NoSuchAlgorithmException e1) {
			e1.printStackTrace();
		}
		return convertToHex(input);
	}
	
    private static String convertToHex(byte[] data) { 
        StringBuffer buf = new StringBuffer();
        for (int i = 0; i < data.length; i++) { 
            int halfbyte = (data[i] >>> 4) & 0x0F;
            int two_halfs = 0;
            do { 
                if ((0 <= halfbyte) && (halfbyte <= 9)) 
                    buf.append((char) ('0' + halfbyte));
                else 
                    buf.append((char) ('a' + (halfbyte - 10)));
                halfbyte = data[i] & 0x0F;
            } while(two_halfs++ < 1);
        } 
        return buf.toString();
    } 


}